Professor Philip Asare (electrical & computer engineering)

"Human Health: The Way We Think About It Affects What We Do About It"

Patients, medical professionals and engineers are continually looking for ways to make the health system more effective, accessible, and cost effective. The trend is in medical technologies that are relatively simple in terms of their goals, but very complex to actually design and realize. Before these technologies are available for use, they must go through the regulatory system. In the US, this means they must be approved by the FDA. However, as these technologies get more and more complex in their design, we are realizing that our current approaches for evaluating medical technologies are reaching their limits. Part of this has to do with the way we think about "health" and "patient safety". We believe that because these ideas are not well-defined today, we have no useful way to adapt them to the changing technology landscape.

This work is reexamining the ways of thinking about "health" and "patient safety". We use ideas from medicine, policy, mathematics, engineering, and computer science. A STEM scholar on this project will learn to apply these ideas to various examples of diseases from different areas in medicine, to show how we can express clearly what we mean by "health" and "patient safety" so these can be adapted to new technologies and help them become available for use much faster. || Learn more about Professor Asare.

Professor Karen Castle (chemistry)

"Climate Modeling of Terrestrial Planet Atmospheres"

Our group is interested in cooling and heating mechanisms in the upper atmospheres of terrestrial planets. We use laser spectroscopy as a tool to measure rate coefficients of relevant energy transfer processes that contribute to atmospheric heating and cooling. Accurate knowledge of the important rate coefficients is necessary to correctly interpret data being acquired by NASA satellite missions such as TIMED/SABER (Earth-based) and the MAVEN (Mars-based). The rate coefficients are also crucial input parameters in the aeronomic models being used to track long-term climate change.

Students working in this laboratory will gain experience using different kinds of lasers and other sophisticated spectroscopic equipment, acquiring and analyzing data, and assisting with experimental design. || Learn more about Professor Castle.

Professor Will Kerber (chemistry)

"Chemical Models of Metalloproteins"

A dozen or so metals from the periodic table are essential for life and about a third of all proteins require metal ions to achieve their intended biological function. Proteins are synthesized in cells without metals and must somehow find the correct one to become active.

We are interested in how nature has tuned the structure of proteins to select for a specific metal ion. We prepare organic molecules (ligands) that mimic the metal binding sites of proteins. We study how mixtures of metals compete for the ligand, with the goal of understanding how the structure of the ligand and its 3D arrangement in space affect metal binding affinity. || Learn more about Professor Kerber.

Professor Martine (biology)

"Botanical Collections"

Recent research expeditions by our lab have resulted in the collection of hundreds of unusual botanical specimens from Australia and Hawaii. These specimens, as representative vouchers of our work, require preparation and permanent preservation in Bucknell's Manning Herbarium.

The STEM fellow will be trained to curate natural history specimens, including specimen identification,mounting, and databasing. Additionally, the student will participate in local collecting trips to help expand the collections of local species currently held in our herbarium. They will join an active group of undergraduate researchers already working in the lab, with the potential to develop an independent project. || Learn more about Professor Martine.

Professor Le Paliulis (biology)

"How Chromosomes Communicate with One Another over a Distance"

The Paliulis group studies the key differences between metaphase and anaphase chromosomes, and one project concerns how chromosomes communicate with one another over a distance. A number of organisms have chromosomes that do not pair and stick together in meiosis I but almost always separate correctly from one another. Somehow the position of one chromosome is "communicated" to its partner chromosome.

We have been studying this phenomenon in spiders (black widow and yellow sac), showing that partner chromosomes only complete meiosis I when they are correctly positioned relative to one another. We are currently examining Mesostoma ehrenbergii, a flatworm with multiple chromosomes that display distance interactions. || Learn more about Professor Paliulis.

Professor Marie Pizzorno (biology)

"Rapid Isolation and Identification of Arthrobacterphage"

Bacteriophage, or phage, are viruses that can use bacterial cells as their hosts. Infection of a bacterial cell with a phage usually results in the production of new virus particles, called a lytic infection. Lytic infections produce plaques in lawns of bacterial cells and isolating plaques is how new phage can be isolated. We are studying phage that can infect an Arthrobacter host species. Almost all of the phage we have isolated on this host have very small genomes of double-stranded DNA (~15kbp).

The goal of this project will be to develop techniques for the rapid isolation and identification of Arthrobacterphage with more diverse genomes. The techniques will include growing bacteria, isolating phage using plaque purification, DNA isolation, restriction enzyme digests, agarose gel electrophoresis, and possibly polymerase chain reaction. || Learn more about Professor Pizzorno.

Professor Nathan Ryan (mathematics)

"Quantifying how Equitable the Distribution of Healthcare is in the United States."

Over the past couple of semesters, students and I have, using code we have written, assigned health access scores to regions all over the United States: the bigger the score, the more physical access the people in that region have to healthcare. The next step is to determine how equitably these scores are distributed. In particular, we will compute the Gini index of these data and also disaggregate the data by demographics and by geography to better see what our distribution of equity scores depends on.

A student will run statistical tests on these data sets, interpret the results and help write the results section of a research paper. || Learn more about Professor Ryan.

Professor George Shields (chemistry)

"Mechanism for Formation of Secondary Aerosols"

In a warming world, the biggest uncertainty in modeling global feedback mechanisms is the formation of clouds. Secondary aerosols form from ions and molecules in the atmosphere, and clouds form from aerosols. In general clouds are thought to be a negative feedback system for global warming, so that as cloud cover increases more incoming sunlight is reflected back into space, thus leading to a cooling effect. However, because the mechanism for secondary aerosol formation is unknown, there is still a very large uncertainty in the feedback mechanisms.

The Shields group is using computational chemistry to model the formation of secondary aerosols, and collaborating with experimentalists to fill in the gaps in our uncertainty about these essential processes. || Learn more about Professor Shields, Dean of the College of Arts and Sciences.

Professor Tom Solomon (physics & astronomy)

In a forest fire, the dividing line between burned and unburned trees is called a front. The motion of this front determines how the fire spreads through the forest. Similar front dynamics characterize the spreading of a disease in society, as well as numerous chemical processing applications, biological processes in cells and developing embryos, and plasmas in fusion reactors. We are currently conducting experiments that explore how the motion of fronts is affected by fluid mixing, e.g., forced flows in a chemical processor, winds in a forest fire, or the motion of people in society while a disease spreads. Table-top experiments using a simple chemical reaction (the well-known Belousov-Zhabotinsky reaction) focus on how fronts are affected by simple flow patterns — vortices (whirlpools) and jets.

We are currently testing theories of "burning invariant manifolds" (BIMs) that predict barriers impeding the motion of fronts in simple two- and three-dimensional flows. We are also studying BIM-like barriers that impede the motion of bacteria swimming in fluid flows. There is a lot of "hands-on" work involved in these projects, including the designing, building and testing of the experimental apparatus, mixing chemicals for the reaction or culturing the bacteria, and doing numerous experimental data runs. The experimental work also involves a substantial amount of computer-aided image analysis, almost exclusively on Linux workstations running a program called IDL. || Learn more about Professor Solomon.

Professor Mark Spiro (biology)

How do hormones and light interact to control chloroplast movement?

Plants use light to fuel the process of photosynthesis, but light can also be used by plants as an environmental signal, light as information rather than energy. Light information is perceived by photoreceptors and is converted into signals that direct developmental responses including photomorphogenesis, phototropism and chloroplast relocation. Chloroplast relocation allows chloroplasts to change position in order to maximize light absorption for photosynthesis or to avoid oxidative damage and inhibition of photosynthesis. Under weak light, chloroplasts are positioned along the cell surface perpendicular to incident of light, the periclinal walls, creating a response called "accumulation movement". On the other hand, when irradiated with strong light, chloroplasts move to the sides of the cell, the anticlinal walls, in an "avoidance movement". Plants grown in darkness accumulate chloroplasts at the anticlinal walls although the physiological role is unknown. Studies about chloroplast movement have shown that phytochrome is the main photoreceptor that mediates chloroplast relocation using both red and blue light signals. How do light signals cause developmental changes in plant cells? Evidence suggests that the plant hormone cytokinin plays an important role in mediating light signaling. Cytokinin concentrations increase upon exposure to light and cytokinins can induce light-mediated developmental processes promoting photomorphogenesis in the dark.

In this study we will work with Ceratopteris richardii (C-fern) to investigate the role of cytokinins in signaling an early accumulation response of chloroplasts as mediated by dim white light in the presence or absence of cytokinins. We predict that cytokinins will shorten the lag time in the movement of chloroplasts in dark-grown C-fern from the anticlinal to periclinal walls. This study will help us to identify a rapid response that is regulated by light and hormones in plants and ultimately to identify target genes that are involved in regulating chloroplast movement and transmitting light signals in plants.

Professor Jennie Stevenson (neuroscience)

"Oxytocin and Alcohol Consumption"

Oxytocin is a neurohormone has been shown to promote healthy social behavior, dampen stress responses, reduce anxiety, and signal satiety (the feeling that you have had enough of something). It is possible that alcohol produces behavioral and physiological changes such as disruption of social relationships, altered stress reactivity, and dysregulated reward systems by disrupting natural oxytocin systems in the brain and body. We are investigating the relationship between oxytocin and alcohol consumption by performing alcohol consumption experiments in a species called prairie voles, a rodent species that readily consumes high amounts of alcohol. Recent data from our laboratory has shown that chronic alcohol consumption in prairie voles reduces oxytocin expression in the anterior (front) part of a brain region called the paraventricular nucleus of the hypothalamus (PVN). In addition, we found a strong negative correlation between the amount of oxytocin expressed in the posterior (back) part of the PVN and the amount of alcohol animals consumed; that is, the less oxytocin there was in the posterior PVN, the more the animal drank. It is important that we follow up on these findings to further characterize alcohol-induced alterations in oxytocin. In particular, we hope to determine if the animals started out with low oxytocin and that is why they are high alcohol drinkers, or if animals that were high alcohol drinkers had a larger effect on their oxytocin in the posterior PVN.

This project will involve giving animals access to alcohol for varying periods of time (3 days to 2 months). Then the animals are euthanized, their brains are removed, and we begin the process of slicing and staining their brains using a technique called immunohistochemistry that allows us to localize and quantify oxytocin in specific parts of the brain. Then we mount the brain tissue onto slides to analyze the staining. Your part in the study will be to participate in the end of the drinking phase, and perform the immunohistochemistry and analysis of oxytocin levels in the brain. The results of this study will help us understand the exact relationship between alcohol consumption and levels of oxytocin in the brain and will shed new light on how alcohol is associated with this neurohormone that is critical for healthy social behaviors and stress systems. || Learn more about Professor Stevenson.

Professor Emily Stowe (biology)

"Investigating viral Diversity in Soil Samples"

Most soils support complex communities of microbes, including viruses. During this project the STEM scholar will learn and use molecular and microbiological techniques to investigate the diversity of viruses to specific bacteria in soil samples taken from campus. Questions I am hoping to answer are: 1) How many categories of virus are in a soil sample? We'll answer this by developing a PCR assay from known viruses to test on DNA isolated from soil samples. 2) Are the viruses equally distributed throughout the first 6-8 inches of the soil? We'll isolate viruses from specific layers of the soil and see if each layer yields the same diversity. 3) What experimental protocols yield the largest diversity of viruses from a sample?

All experimental designs can be optimized, the student will test current methods and develop adjustments to the protocols to increase virus yield. There is a high likelihood of the stem scholar isolating a virus new to scientists. The STEM scholar will work in a lab with other upper-class research students and may do additional experiments to support their projects in understanding bacterial diversity. The STEM scholar will learn techniques such as DNA isolation, virus isolation and plaque purification, PCR, cloning and sequence analysis. || Learn more about Professor Stowe.

Professor Rebecca Switzer (cell biology/biochemistry)

"Activity of DNA Methyltransferases"

Our DNA functions to store our genetic information; the sequence of our DNA provides the sequence for protein synthesis. However, more information is needed – genes must be expressed at the right time and place. One way to control gene expression is epigenetics, heritable changes in genome function that do not alter the underlying DNA sequence. In humans, a common epigenetic mechanism of gene control is site-specific methylation of cytosine; DNA methylation is a repressive mark that prevents gene expression. DNA methyltransferases (DNMTs) are responsible for establishing and maintaining methylation patterns in cells. Changes to the normal methylation pattern are associated with the development of many diseases, including neurological disorders and cancer.

My lab is interested in learning about the activity, regulation, and inhibition of these important enzymes. To do this, we separate the proteins from the complexities of the cell and study their properties in detail. Current work in the lab is focused on developing small molecule inhibitors of DNMTs and understanding the biochemical consequences of disease-causing mutations. Students in my lab gain experience with many common biochemical techniques including protein expression, protein purification, and enzyme kinetics. || Learn more about Professor Switzer.

Professor Mizuki Takahashi (biology)

"Ranavirus Infection Among Local Amphibians"

Our research group is interested in ethology, ecology, and conservation of amphibians (frogs and salamanders). One of our summer projects aims to examine the prevalence of ranavirus infection among local amphibians. Amphibians are the most threatened group of vertebrates and diseases caused by pathogens such as ranavirus and chytrid fungus have driven extinctions of many amphibian populations across the globe.

A STEM scholar will work with the team to survey streams, ponds, and lakes in central Pennsylvania for common amphibian species such as American bullfrog, Green frog, and eastern newts that are known to be susceptible to ranavirus infection. This work involves hiking, wading through streams and ponds, and handling amphibians in the field condition. In addition, a STEM scholar will potentially work on dissection of amphibians and molecular analyses to examine the severity of viral infection. || Learn more about Professor Takahashi.

Professor Brian Utter (physics & astronomy)

"Jamming and Flow of Granular Suspensions"

Our lab focuses on experimental studies of granular materials and multiphase flows, such as particle-fluid suspensions. In these "complex systems," relatively simple building blocks interact through nonlinear forces such that complicated behavior emerges. For instance, a large number of solid grains interacting simply through friction and collisions can produce the sudden avalanching of a hillside or the spontaneous plugging of supply lines in industry. This striking phenomenon, known as the jamming transition, depends on factors such as the local geometry of particles, velocity fluctuations, and stresses, and is observed in a wide variety of physical systems. Adding an interstitial fluid can further complicate matters. We study simplified lab-scale models of these granular/fluid systems to characterize jamming and flow in these systems.

Specific goals for this summer include conducting experiments on the motion of grains in a suspension through a counter-flowing stream of particles or through a network of fixed obstacles. This project will involve collecting experimental data across a wide range of parameters, analyzing video data through computer-aided image analysis, and extracting flow and jamming statistics, to help elucidate the nature of this transition. || Learn more about Professor Utter.

Professor Corrie Walton-McCauley (civil & environmental engineering)

"Studies on the Possibility of Collapsible Bentonite Seal"

In the geotechnical lab this summer, one focus is to analyze the hydraulic influences on pressures of partially saturated bentonite seals used in radioactive waste disposals for increasing (due to swelling) and release (due to collapse) of pressures. These pressures may be affected by the development of negative pore-water pressure, and that property will be studied using principles of unsaturated soil mechanics. The research will try to answer these questions. Is there a defined threshold swelling pressure that could be correlated to the presumed collapse behavior of the bentonite?

The research will provide for an evaluation of the bentonite behavior at the pressure release point (collapse) and how this can compromise the safety of the nuclear waste disposal site. Selected student(s) will have an interest in soils engineering and don’t mind getting their hands dirty in the lab. || Learn more about Professor Walton-McCauley.

Professor Constance Ziemian (mechanical engineering)

Additive manufacturing (AM) methods (such as 3D printing) are capable of fabricating components having complex geometrical shapes in a single step process. Although traditionally used for rapid prototyping, AM methods are evolving into manufacturing processes intended to produce functional components for end use in marketable products. This advancement requires that a thorough understanding of the mechanical properties and behavior of AM parts exists.

This project is an extension of ongoing research focused on the cyclical fatigue performance of AM components. A STEM scholar who joins this effort will be working together with another undergraduate researcher involved in the design, fabrication, residual strength testing, and performance analysis of AM specimens made by fused deposition modeling and subjected to cyclical loading. || Learn more about Professor Ziemian.

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